Effect

Generation I

Light Screen doubles the user's Special when the opponent damages the user with a special move.

Light Screen will fail if the user is already under its effect. The effect of Light Screen is ignored by critical hits. If Light Screen causes the user's special to reach 1024 or higher at any time during battle calculations, it will be reduced mod 1024.

If multiple Pokémon are present on the user's side of the field, all of them are protected by Light Screen, but special damage is only reduced by a third rather than half.

Light Screen is removed from a Pokémon's side of the field if an opponent uses Brick Break or Shadow Shed on it (even if it is immune to Brick Break due to being Ghost-type), unless it is protected from the move or the move misses.

Generation IV

Light Screen is removed from a Pokémon's side of the field if any Pokémon (including an ally) uses Brick Break or Defog on it (even if it is immune to Brick Break due to being Ghost-type), unless it is protected from the move or the move misses.

If Light Clay is held when Light Screen is used, it will extend the duration of Light Screen from 5 to 8 turns.

Generation V onward

Light Screen is removed from a Pokémon's side of the field if it is hit by Brick Break, Defog or Psychic Fangs. Light Screen is not removed if the target is immune to the move (e.g. a Ghost-type Pokémon targeted by Brick Break). Pokémon with the Ability Infiltrator ignore the effects of Light Screen when attacking.